Oc-1 Measurement of the Wavelength of Light Using a Ruler
Published: Wednesday 15 March 2006 - Updated: Thursday 19 April 2007
Aim
To obtain a measurement of the wavelength of light using diffraction markings on a ruler.
Apparatus
- Laser
- Ruler with half mm divisions
- Optical bench
- Tape measure
Diagrams
Click on pictures to enlarge.
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Description
The experimental setup shown above uses the half mm markings as a reflection grating. By measurement of the distance to the image and the distance between interference maxima simple calculation yields lambda.
Taking O as the origin (the mid point between the zeroth order specularly reflected beam and the direct beam) the condition for constructive interference is given by the equation above.